The State and Viability of Russia's Nuclear Arsenal in 2025

How robust is Russia's nuclear deterrent?

Picture: Ministry of Defense of Russia

Russia’s war on Ukraine has exposed serious shortcomings in Russia’s conventional military capabilities. Some argue that these deficiencies may extend to its nuclear forces as well. In this post, I want to assess the state of Russia’s nuclear arsenal in 2025 and examine how robust its nuclear deterrent remains amid mounting challenges.

Nuclear arsenal maintenance

Maintaining a robust nuclear deterrent presents Russia with two key challenges. First, it must ensure its nuclear warheads remain operational. Second, it must sustain a functional fleet of delivery vehicles. Both appear manageable in the short term, but challenges are likely to intensify over the medium to long term.

Nuclear warheads

Nuclear warheads require regular maintenance, particularly their plutonium pits. The pit, which serves as the core of an implosion-type nuclear weapon, must be symmetrically compressed by precisely timed conventional explosives to initiate a nuclear chain reaction. Any deviation in timing or symmetry can reduce the warhead’s explosive yield or, in the worst case, prevent fission from occurring altogether.

Plutonium pits degrade over time and generally need replacement every 10 to 15 years, meaning Russia has likely undergone at least two full cycles of pit refurbishment since the Soviet Union’s collapse. This means that while the loss of Cold War-era warhead manufacturing expertise is likely a concern, the knowledge has likely been passed down somewhat effectively. Furthermore, while pit refurbishment demands precision manufacturing techniques, it is not necessarily reliant on Western precision manufacturing tools, as it does not require large-scale industrial production.

Another potential issue with warhead maintenance is tritium replenishment. Tritium, a radioactive hydrogen isotope, is used in boosted fission weapons to enhance the efficiency of the fission process. With a half-life of roughly 12.5 years, half of a given tritium stockpile decays roughly every decade, requiring replenishment every 5 to 10 years.

Tritium production is complex, involving advanced radiation and separation techniques, but unless something has gone seriously wrong within Russia’s nuclear weapons enterprise, the necessary expertise has likely been retained. Another challenge is cost, as maintaining tritium levels across Russia’s arsenal requires an estimated $100,000 per warhead per maintenance cycle. This being said, Russia can partially offset costs by recycling tritium used in retired warheads.

In sum, Russia should be able to maintain its nuclear warheads in the short to medium term, though this upkeep imposes a significant financial and opportunity cost. As other nuclear weapon states, including the U.S., France, and the UK, understand very well, every resource spent on nuclear maintenance is a resource not available elsewhere. In peacetime, this tradeoff is manageable, but in the midst of a high-intensity attritional war, it can become a serious financial strain. But in any case, assessments that Russia’s nuclear warheads have turned into a paper tiger appear unwarranted and unwise.

Delivery vehicles

Upkeep and modernization challenges are likely more pronounced in Russia’s fleet of delivery vehicles, particularly intercontinental ballistic missiles.

The last major innovation in Russian ICBM design—rather than an evolution of an existing system—dates back to the RS-12M Topol (SS-25 "Sickle"), developed in the late 1970s and early 1980s. The RS-12M Topol was the first Soviet ICBM design to achieve true road mobility.

Since then, all subsequent Russian ICBMs, as well as several shorter-range ballistic missiles, have been evolutions of earlier designs, including:

• RS-12M2 Topol-M (SS-27 Mod 1) → A direct descendant of the RS-12M Topol (SS-25 “Sickle”).

• RS-24 Yars (SS-29 Mod 2) → Essentially a MIRVed RS-12M2 Topol-M.

• RS-28 Sarmat (SS-X-30) → Successor to the R-36M2 (SS-18), maintaining the same heavy-liquid ICBM concept.

• UR-100NUTTH with Avangard (SS-19 M4) → A repurposed Soviet-era UR-100N (SS-19) carrying a hypersonic glide vehicle.

• RS-26 Rubezh (the Oreshnik precursor) → A scaled-down RS-24 Yars.

Thus, in over 40 years, Russia has not introduced a truly new ICBM concept—all have been modifications, upgrades, or repurposed systems.

Even more concerning from a Russian perspective, Moscow appears to have hit a technological and industrial bottleneck with the RS-28 Sarmat (SS-X-30). Originally slated for operational deployment in 2018, the missile has yet to be fielded. Its most recent test in September 2024 ended in catastrophic failure.

Russia’s inability to bring its next-generation ICBM into service—or even make significant progress—over such an extended period points to systemic issues within its defense industry, particularly a lack of expertise in ICBM development and production. These delays could place increasing pressure on Russia’s aging arsenal in the medium to long term.

Reports indicate that Russia has so far sustained its ICBM fleet by using decommissioned Soviet and Russian ICBMs retired under U.S.-Russia arms control agreements for spare parts. Open sources do not clarify how many retired missiles remain or how effectively they can be used for this purpose. However, this supply is finite, and at some point, Russia will no longer be able to rely on Soviet stockpiles. If no domestic alternative is in place by then, the reliability of Russia’s strategic nuclear arsenal will inevitably decline.

Keep in mind also that reliability issues in delivery vehicles pose a far greater challenge than in nuclear warheads. Since most ICBMs carry multiple warheads, a systemic failure in a delivery vehicle could result in the loss of several warheads at once.

The outlook is less dire for non-strategic or tactical nuclear warhead delivery vehicles. The war in Ukraine has demonstrated that Russia can produce short-range ballistic missiles and land-attack cruise missiles in large numbers, and these systems could serve as viable nuclear delivery vehicles for nuclear warheads in a European contingency, though they would be unable to threaten U.S. homeland targets.

While Western sanctions have affected the reliability and accuracy of these shorter-range missiles, Russia has managed to replace Western components with either domestic alternatives or third-party substitutes not yet subject to restrictions. As a result, Russia’s non-strategic nuclear arsenal is likely in a much stronger position over the medium to long term compared to its strategic nuclear forces.

Implications

What does this mean for the future of Russia’s nuclear deterrent? The available data is insufficient to make sweeping claims about the robustness of Russia’s nuclear arsenal. Those who argue that Russia no longer maintains a functioning deterrent are extrapolating from limited information, and such claims are not justified.

That said, Russia’s nuclear arsenal, particularly its strategic deterrent, faces serious challenges over the medium to long term. To maintain a robust nuclear deterrent Russia must position itself to sustainably produce ICBMs, but at present, it does not appear able to achieve this. The issue here is not primarily a lack of funding (though financial constraints amid competing priorities likely play a role) but deeper systemic weaknesses in its defense-industrial base, similar to those seen in other areas.

Russia is not alone in facing these difficulties. The UK struggles to sustain its nuclear deterrent and remains heavily reliant on U.S. support, a dependence that appears increasingly problematic. The U.S. has encountered cost overruns and delays in its next-generation ICBM program, likely for similar reasons Russia faces, namely that Cold War-era expertise was lost, requiring the defense-industrial base to be rebuilt. The key difference is that the U.S. has the financial resources to throw at the problem and access to a far larger, more capable talent pool than Russia.

Two key implications stand out:

First, from a more theoretical perspective, Russia’s nuclear arsenal has long been considered the most robust among U.S. adversaries due to its diversity and size (both in academic literature and policy discourse). By contrast, China’s arsenal has traditionally been viewed as more limited, providing only a minimal assured retaliatory capability.

Given Russia’s mounting difficulties in maintaining its arsenal and China’s clear ability to expand both deployed warheads and strategic delivery vehicles, China today may actually field a more robust nuclear deterrent than Russia. This is especially true when considering not just deployed or readily available capabilities but also latent production and maintenance capacity—most notably, a functioning defense-industrial base capable of sustaining nuclear forces over time.

Second, from a policy perspective, Russia will need to find answers to these challenges, particularly regarding its strategic deterrent. One possible response could be to expand the role of its non-strategic nuclear arsenal. I would therefore not be surprised if future Russian policy documents may argue that non-strategic nuclear weapons should no longer serve only escalation management functions, as they currently do, but also play a role in countervalue targeting—direct strikes on European cities. In doing so, Russia may seek to substitute some of the functions of its strategic nuclear deterrent, particularly if its ability to maintain a credible ICBM force continues to deteriorate.